Lifting device



Oct. 27, 1931. E. OEH MICHEN 1,323,783

LIFTING DEVICE Filed Aug. 12. 1929 2 Sheets-Sheet l Oct. 27, 1931.

E. OEHMICHEN LIFTING DEVICE 2 Sheets-Sheet 2 Filed Aug. 12, 1929 Patented a.. 27, 1931 UNITED STATES ETIENNE OEHMIGEEN, OI VALENTIGNEY, FRANCE IJJ'TIN G DEVICE Application filed August 12, 1929, Serial No. 885,140, and in France June 18, 1926.

lows: under the influence of a relative wind non-parallel to the axis of this lifting device, or simply owing to a permanent defect of homogeneity of the aerodynamic field, the reactions of the air on each blade of the lifting device at the various points of its trajectory alternately pass through a maximum and a minimum very approximately located on one and the same diameter of the circle described by the blade.

The plane in which are located the maxnna and minima of the reactions of the .air on the blade under consideration has been designated under the term of plane of maximum unbalance.

The researches made by the applicant concerning the distribution of the air on a blade in motion have shown that the axis of rotation of the lifting device would tend to upset itself, not, as could be expected, in the maximum balance 1plane, but in a plane exactly at right ang es to the preceding one, and this owing to the gyroscopic effects of the blade itself.

If it is desired to re-establish the equilibrium of the apparatus, the greatest correction of the incidence of the blades, which must necessarily occur when the blades pass through the plane of maximum unbalance, must then take place at the moment these blades are directed in the plane perpendicular to the upsetting plane of the apparatus.

It is to be understood that provisions can be made for correcting the incidence on the entire blade, or on an element only of this blade, the practical result being the same in both cases.

The present invention relates to the application of the above mentioned principles to a lifting device in which the incidence of the blades can be modified by the pilot himself, for modifying this incidence according to the reactions of the air on the elements of the lifting device in course of rotation.

As just stated, it is necessary to correct the incidence, not as it has been effected up to now in certain known apparatus, that is to say by correcting to the maximum the in cidence of the blades when they pass through the upsetting plane itself, but, on the contrary, by producing the maximum correction when they are directed in a plane at right angles to the saidupsetting plane. This can be obtained by means of a suitable power transmission, which can be of any-type. As the reflex reactions of the pilot cause him to operate the control member or balancing member in the upsetting plane of the apparatus, the essential character of this transmission consists in that it is adapted to produce the maximum of correction of incidence, in a plane in which the said balancing member or joy stick is moved by the pilot.

Such a control can be easily carried out in a large number of different ways; two forms of construction only will be described, by way of example, with reference to Figs. 1 and, 2 which illustrate dia rammatically and in perspective these two orms of construction.

These drawings more particularly relate to the case of a lifting airscrew which is to be balanced, but the invention is applicable to all propellers subjected to a relative wind non parallel to their axis of rotation and for which it is desired to annul the upsetting moments.

Fig. 1 relates to a lifting device in which the incidence of the blades 1, l, is controlled, on the one hand, automatically under the influence of the reactions of the air on an auxiliary airscrew 2, 2 arranged above the lifting airscrew, and, on the other hand, at the pilots will, when the pilot moves the control lever or jo stick 3, this displacement being instinctive y produced in the upsetting planeof the apparatus and in opposite direction to upsetting.

The said automatic control through the airs'crew 2, 2, is in agreement with that forming the subject-matter of the abovementioned patent application and will not be claimed here per se, the present invention 10p more particularly referring to the control of the incidence of the blades by the pilot.

In this form of construction, the liftin air-screw has two blades 1, 1, rigidly secure on a bar 4 which is rotatively mounted in a bearing 5 carried by a driving shaft 6, which is guided in a fixed tube 7. On this tube, a Cardan ring 8 can oscillate about trunnions 9 and sup orts, by means of trunnions 10, a ring 11 adapted to be actuated by the automatic regulator 2, 2 and by the pilot.

The regulator has blades 2, 2 secured on a bar 12 rockable about a transverse shaft 13 carried bytwo yokes 14 rigid with the hearing 5 this shaft 13 being parallel to the bar 4 of the lifting airscrew.

' This regulator controls the incidence of the blades 1 by means of a fork 15, rigid with the bar 12 and acting on a yoke 16 rigid with the bar 4.

For compelling the ring 11 to remain parallel to the bar 12 of the regulator, two links 17 for instance, can be provided, these links being pivotally connected, by means of trunnions 18, to the bar 12, and by means of spherical members 19, to a collar 20 guided on the periphery of the ring 11, so as to be capable of freely rotating about the latter.

The control lever 3 is pivoted, through a in 21, on a shaft 22 mounted in a fixed bearmg 23; this shaft carries an arm 24 orthogonally directed relatively to the pin 21.

The ring 11 is connected to the said lever 3 and arm 24 by wires 25, 26 27, 28; the wires 25 and 26' are attached to the lever 3 at two points a and 5 located at the ends of a diameter of this ring. On the other hand, the wires 27 and 28 are attached, at point 0, to the arm 24, and at points 0 and d to the ring 11, according to a diameter perpendicular to (1 6 All these wires pass over transmission rollers 29 suitably arranged.

The operation is as follows:

The connection being adjusted in such a manner that the ring 11 is horizontal when the control lever 3 is vertical, it will be seen that if the latter is pushed from this osition towards, the ring, the said ring will e compelled to rock towards the control lever, as illustrated. If the control lever is inclined from the vertical position towards the right of the plane of the shafts 6 and 22, the wire 27 is released and the wire 28 is pulled so that the ring 11 will be compelled to rock towards the left of this plane.

Generally speaking, this ring will rock in reverse direction to the lever 3, itsdiameter of greater slope being always brought in a vertical plane substantially parallel to the vertical plane in which the control lever will be set.

Owing to the connection constituted by the ring 20 and the links 17, the bar 12 is compolled to remain parallel to this ring. The fork 15, perpendicular to the bar 12 and rotating with the latter, takes a variable inclination and this inclination becomes maximum when the direction of this bar 12 is parallel to the line of greatest slope of the. rin 11, and, consequently, it gives to the bla es 1, 1 the greatest correction of incidence when these blades are directed at right angles relatively to the said line of greatest slope of the ring 11, that is to say at right angles relatively to the plane of orientation given to the lever 3 by the pilot; plane which is caused LO coincide, by the reflexes of the pilot, with the upsetting plane of the apparatus.

Thus, the pilot therefore instinctively obtains the maximum correction of the blades 1, 1, when the latter pass through the unbalancing plane, as is necessary for reestablishing the equilibrium of the apparatus.

This construction allows of combining the control of the incidence by the automatic regulator, without these controls mutually interfering, since the pilot instinctively acts in the same direction as the regulator.

Of course, the control by the pilot, which const1tutes the main object of the present patent application, can be employed alone and the construction can then be simplified, for instance as indicated in Fig. 2.

In this example, the bar 4 carrying the blades 1, l of the lifting airscrew is rotatively mounted in a sleeve 31 which, in its turn, is mounted, by means of trunnions 32, in a fork piece 33 rigid with the driving shaft 6, the axis of these'trunnions being perpendicular both to that of this shaft and to that of the sleeve of the bar 4.

The incidence of, the blades 1, 1 is controlled from the control lever 3 by the following transmission:

On fixed trunnions 34 can oscillate a Cardan ring 35 within which a plate 36 can rock about trunnions 37, the axis of which is at right angles to that of the trunnions 34. The lever 3 is rigidly secured to the plate 36 and can thus rock in any direction.

On the other hand, fixed trunnions 38 carry a Cardan ring 39 which supports, by means of other trunnions 40, a plate 41 having a central opening through which the shaft 6 freely passes. The axes of the trunnions 38 and 40 are at right angles and their crossing point islocated on the axis of the shaft 6.

The plates 36 and 41 are connected together, so that the rotations and inclinations imparted to one of them are also transmitted to the other. For instance, they are connected by wires 42, 43, 44, 45 and attached at points 9 h i j, g, h, 2', j of these two plates as shown in Fig. 2.

Finally, the shaft 6 carries a transverse axis 47, on which is mounted a bent lever 48,

one end of which carries a roller 49 moving on the plate 41 and the opposite end carries a fork piece 50 extending above the sleeve 31 and fitted on a finger 51 rigid with the bar ing 52 of the sleeve 31.

The positions of the points 9 h i and g h i on both plates are so chosen that, at the moment the bar 4 is directed in a. plane perpendicular to the diameter of greatest slope of the plate 36, and, consequently, perpendicular to the plane of orientation of the control lever 3, the plate 41 presents under the roller 49 its diameter of greatest slope,

in order to give to the incidence of the blades 1, l the maximum correction by the action of the lever 48 on the finger 51. On the contrary, when the bar 4 is directed in a plane parallel to the horizontal diameter of the plate 36, the plate 41 presents under the roller 49 its horizontal diameter and the incidence of the blades 1, 1 again becomes normal.

An auxiliary motor could also be advantageously provided, which would borrow its energy either from the engine of the apparatus, or from any source and allowing to transmit the movements of the control lever to the airscrew for a very small energy exerted by the pilot; this would have for advantage to diminish in a large proportion the physical fatigue for piloting the apparatus.

The incidence of a blade can be adjusted as just stated by simple rotation of the said blade about its longitudinal axis, this modi fying the angle formed by the blade with its plane of rotation.

But the incidence of the blade relatively to the air can also be modified by displacement of the entire blade about an axis at right angles to the propeller-carrying'shaft and nonarallel to the great axis of the blade. T is' latter method may be considered as a variation of the incidence through the trajectory of the blade. In fact, if the latter rises at the same time as it rotates, its absolute incidence relatively to the air is diminished, and if it lowers durin its rotation,.its incidence is increased. he modification of the trajectory of the blade can be obtained either automatically by allowin the latter to oscillate under the influence o the reactions of the aerodynamic field, or by compelling the blade to move out from its normal lane of rotation by an device, but according to the principles 0 the present invention, that is to say by modifying to the ma'x'imum the incidence of the blades in a plane at right angles to the upsetting plane. of the apparatus.

Claims:

1. Lifting device comprising the combi-- nation of a system of liftlng blades continu- Ol sly rotating about a main axis of rotation and the incidence of which is variable. and means for controlling the incidence of the said blades, these means comprising levers controlling the incidence of the said lifting blades, an operating member universally jointed about a point of the said main rotary axis and serving to control the said levers, a steering lever adapted to be operated by the pilot and connecting members between the said lever and the said operatin member, the incidence of each system o lifting blades being rendered maximum or minimum when the said blades pass through a plane at right angles to the reversing plane of the system of blades.

2. Lifting device comprisin the combination of a system of lifting bla es continuously rotatin about a main axis of rotation and capable o rocking, on the one hand, about their longitudinal axis so that their incidence can vary and, on the other hand, about an axis at right an le to their longitudinal axis,

are operatively connected, a steering lever adapted to be operated by the pilot, and connecting members between the said .steerin lever and the said late, the incidence of eac system of lifting blades being rendered maximum or minimum when the said blades pass through a plane at right an les to the reversing lane of the system 0 blades.

3. Li ing device comprising the combination of a s stem of two liftin blades, 8. bar on which both blades are rigi ly secured a sleeve in which the said bar can rotate an on which are provided two trunnions a. driv-J ing shaft adapted to actuate the said liftin device, a fork-piece on this driving shaft an in which both trunnions are housed, a finger rigid with the said bar, a lever pivoted on the said driving shaft, a fork-piece at one of the ends of this lever, this fork-piece being fitted on the said finger, a roller at the other end no of the said lever, a first plate capable of bein inclined in all directions and on which the sald roller can run, a second plate ca able of being inclined in all directions an arran ed near the driver, a steering lever rigid n5 wit the said second plate, connecting means between both plates, these connectin means being so constituted that the first p ate exactly follows the inclinations imparted to the second plate by'the said steerin lever and 1 determine a variation of the inci ence of the blades, the maximum incidence occurring in an axial plane at right angles to the plane in which the said steering lever is operated.

In testimony whereof I have hereunto af- 125 

